javax.media.jai.operator
Class RescaleDescriptor

java.lang.Object
  |
  +--javax.media.jai.OperationDescriptorImpl
        |
        +--javax.media.jai.operator.RescaleDescriptor

All Implemented Interfaces:

OperationDescriptor, RegistryElementDescriptor, Serializable

public class RescaleDescriptor

extends OperationDescriptorImpl

An OperationDescriptor describing the "Rescale" operation.

The "Rescale" operation takes a rendered or renderable source image and maps the pixel values of an image from one range to another range by multiplying each pixel value by one of a set of constants and then adding another constant to the result of the multiplication. If the number of constants supplied is less than the number of bands of the destination, then the constant from entry 0 is applied to all the bands. Otherwise, a constant from a different entry is applied to each band. There must be at least one entry in each of the contants and offsets arrays.

The destination pixel values are defined by the pseudocode:

 constant = (constants.length < dstNumBands) ?
            constants[0] : constants[b];
 offset = (offsets.length < dstNumBands) ?
          offsets[0] : offsets[b];

 dst[x][y][b] = src[x][y][b]*constant + offset;
 

The pixel arithmetic is performed using the data type of the destination image. By default, the destination will have the same data type as the source image unless an ImageLayout containing a SampleModel with a different data type is supplied as a rendering hint.

Resource List

Name	Value
GlobalName	Rescale
LocalName	Rescale
Vendor	com.sun.media.jai
Description	Maps the pixels values of an image from one range to another range.
DocURL	http://java.sun.com/products/java-media/jai/forDevelopers/jai-apidocs/javax/media/jai/operator/RescaleDescriptor.html
Version	1.0
arg0Desc	The per-band constants to multiply by.
arg1Desc	The per-band offsets to be added.

Parameter List

Name	Class Type	Default Value
constants	double[]	{1.0}
offsets	double[]	{0.0}

See Also:

OperationDescriptor, Serialized Form

Fields inherited from class javax.media.jai.OperationDescriptorImpl

resources, sourceNames, supportedModes

Fields inherited from interface javax.media.jai.OperationDescriptor

NO_PARAMETER_DEFAULT

Constructor Summary

RescaleDescriptor()
Constructor.

Method Summary

static RenderedOp	create(RenderedImage source0, double[] constants, double[] offsets, RenderingHints hints) Maps the pixels values of an image from one range to another range.
static RenderableOp	createRenderable(RenderableImage source0, double[] constants, double[] offsets, RenderingHints hints) Maps the pixels values of an image from one range to another range.
boolean	isRenderableSupported() Returns true since renderable operation is supported.
protected boolean	validateParameters(ParameterBlock args, StringBuffer msg) Validates the input parameters.

Methods inherited from class javax.media.jai.OperationDescriptorImpl

arePropertiesSupported, getDefaultSourceClass, getDestClass, getDestClass, getInvalidRegion, getName, getNumParameters, getNumSources, getParamClasses, getParamDefaults, getParamDefaultValue, getParameterListDescriptor, getParamMaxValue, getParamMinValue, getParamNames, getPropertyGenerators, getPropertyGenerators, getRenderableDestClass, getRenderableSourceClasses, getResourceBundle, getResources, getSourceClasses, getSourceClasses, getSourceNames, getSupportedModes, isImmediate, isModeSupported, isRenderedSupported, makeDefaultSourceClassList, validateArguments, validateArguments, validateParameters, validateRenderableArguments, validateRenderableSources, validateSources, validateSources

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

RescaleDescriptor

public RescaleDescriptor()

Constructor.

Method Detail

isRenderableSupported

public boolean isRenderableSupported()

Returns true since renderable operation is supported.

Overrides:

isRenderableSupported in class OperationDescriptorImpl

Following copied from class: javax.media.jai.OperationDescriptorImpl

See Also:

OperationDescriptorImpl.isModeSupported(java.lang.String)

validateParameters

protected boolean validateParameters(ParameterBlock args,
                                     StringBuffer msg)

Validates the input parameters.

In addition to the standard checks performed by the superclass method, this method checks that the length of the "constants" and "offsets" arrays are each at least 1.

Overrides:

validateParameters in class OperationDescriptorImpl

Following copied from class: javax.media.jai.OperationDescriptorImpl

Throws:

IllegalArgumentException - if args is null.

IllegalArgumentException - if msg is null and the validation fails.

See Also:

OperationDescriptorImpl.validateParameters(java.lang.String, java.awt.image.renderable.ParameterBlock, java.lang.StringBuffer)

create

public static RenderedOp create(RenderedImage source0,
                                double[] constants,
                                double[] offsets,
                                RenderingHints hints)

Maps the pixels values of an image from one range to another range.

Creates a ParameterBlockJAI from all supplied arguments except hints and invokes JAI.create(String,ParameterBlock,RenderingHints).

Parameters:

source0 - RenderedImage source 0.

constants - The per-band constants to multiply by. May be null.

offsets - The per-band offsets to be added. May be null.

hints - The RenderingHints to use. May be null.

Returns:

The RenderedOp destination.

Throws:

IllegalArgumentException - if source0 is null.

See Also:

JAI, ParameterBlockJAI, RenderedOp

createRenderable

public static RenderableOp createRenderable(RenderableImage source0,
                                            double[] constants,
                                            double[] offsets,
                                            RenderingHints hints)

Maps the pixels values of an image from one range to another range.

Creates a ParameterBlockJAI from all supplied arguments except hints and invokes JAI.createRenderable(String,ParameterBlock,RenderingHints).

Parameters:

source0 - RenderableImage source 0.

constants - The per-band constants to multiply by. May be null.

offsets - The per-band offsets to be added. May be null.

hints - The RenderingHints to use. May be null.

Returns:

The RenderableOp destination.

Throws:

IllegalArgumentException - if source0 is null.

See Also:

JAI, ParameterBlockJAI, RenderableOp